On Sun, 30 Aug 1998 13:28:27 +0900 Satoshi NISHIHARA <nishis at urban.ne.jp> wrote: 
>I've been dazed and confused ((C)Led Zeppelin) by SortedCollection.
>
>    | collection |
>    collection := SortedCollection new.
>    collection sortBlock: [:element1 :element2 | element1 > element2].
>    1 to: 10 do: [:i | collection add: i].
>    Transcript cr; show: (collection copyFrom: 1 to: 5) printString
>
>Got SortedCollection (6 7 8 9 10 ), although expected SortedCollection
>(10 9 8 7 6 ).
>I think that SortedCollection (6 7 8 9 10 ) has sortBlock: [:x :y | x <=
>y] (default) *not* [:x :y | x > y] (required).  Is it right?

You are right about the new SortedCollection having the default sortBlock.

OrderedCollection>>copyFrom:to: creates the new collection with

 self species new: endIndex + 1 - startIndex

This just gives you the same kind (with 2 exceptions) of collection you had before. It does NOT recognize what sortBlock the original had.

To get your code to work, you can:

1. Explicitly give the new collection a sortBlock as in

    Transcript cr; show: ((collection copyFrom: 1 to: 5) 
		sortBlock: [:element1 :element2 | element1 > element2]) printString

2. Or, if you are not interested in the result actually being a SortedCollection,

    Transcript cr; show: (collection asArray copyFrom: 1 to: 5) printString

3. Or you could reimplement #copyFrom:to: in SortedCollection to give the new collection the same sortBlock as the old one had:

copyFrom: startIndex to: endIndex 
	"Answer a copy of the receiver that contains elements from position
	startIndex to endIndex, keeping the sortBlock from the receiver"

	| targetCollection |
	(targetCollection _ self species new: (endIndex + 1 - startIndex max: 0)) sortBlock: self sortBlock.
	endIndex < startIndex ifTrue: [^targetCollection].
	startIndex to: endIndex do: [:index | targetCollection add: (self at: index)].
	^ targetCollection

Cheers,
Bob